Low Noise Operational Amplifier for Smart Dust and IoT Applications

Operational amplifiers (op-amps) are crucial for IoT application but face performance challenges due to shrinking transistor sizes, complicating the optimization of voltage swing, power consumption, and noise. This research presents a rail-to-rail, low-noise, low-power op-amp for biomedical and IoT applications, which features a dual PMOS differential input stage and a push-pull amplifier. Designed in a $0.13 \ \mu \mathrm{m}$ bulk CMOS technology node, it achieves an 84 dB open-loop DC gain, 59° phase margin, 265 nV/√Hz input-referred noise at 1 kHz, and $85 \ \mu \mathrm{W}$ power consumption, with a chip area of 0.0032 mm².